Verify package using debsums
Verify every installed package
debsums
Verify every installed package (including configuration files).
debsums -a
Verify installed packages and report errors only
debsums -s
Verify every installed package and report changed files only
debsums -c
Verify every installed package (including configuration files) and report changed files only.
debsums -ca
Verify every installed package and report changed configuration files only.
sudo debsums -ce
Verify specific package
debsums -a bash
Create mismatch list
dpkg-query -S $(sudo debsums -c 2>&1 | sed -e "s/.*file \(.*\) (.*/\1/g") | cut -d: -f1 | sort -u
To reinstall them
apt-get install --reinstall <package name>